As the days go by, I notice that many people join the wiki instantly. And I think there's only one reason. BADGES AND RANKINGS! Haven't you noticed that many members just showed up in the achievements leaderboard? Some of the editors don't really contribute; they just sometimes delete punctuation marks and put them again. And then they earn a badge after some more edits. They don't realize that the real essence of a wiki is to share ideas and information about a topic (for our case it's Plants VS Zombies). It's to help have informative pages about thing where people can gain new ideas about that particular topic. The badges given are just extras. It's just to motivate us to do more contributions. It's not to be famous. If you are just joining this wiki to be known for being in the rankings, it's better for you to just LEAVE the wiki.
We all know the green welcome template right? We all have them in our talk pages. Admins, I suggest that you add information there telling new users to join the wiki to contribute information and not to be among the rankings and be famous. I also suggest you to add this beside the information about categories in the recent wiki activity page.